Self-propelled crane

ABSTRACT

A self-propelled crane is provided with a mast pivoted on a rotatable platform for movement between a horizontal and a vertical position. A telescopic jib is pivoted on the mast and the same cable and winch used to raise and lower a load from the tip of the jib is used to extend the jib when the telescopic jib sections are unlatched from each other. The same cable and winch may be used to raise the mast to the vertical position by securing the end of the cable to a stationary point below the pivot point of the mast. The mast may also be telescopic and a second cable and winch may be used to control both the angle of the jib relative to the mast and the extension of the telescopic mast when the parts thereof are unlatched from each other.

[72] Inventor Jean Noly Villa Tasco," l quartier Briand, La Clayette, (Saone-et-Loire), France [21 Appl. No. 824,538 [22] Filed May 14, 1969 [45] Patented Jan. 4, 1972 [32] Priorities May 14, 1968 3 3 1 France [3 l 50,015;

May 12, 1969, France, No. 6915332 [54] SELF-PROPELLED CRANE 8 Claims, 32 Drawing Figs. [52] US. Cl 212/46, 212/46 B, 212/144, 212/55 [51] Int. Cl B66c 23/62 [50] Field of Search 212/46 A, 46 B, 55, 56, 8, 144, 46; 254/143 [5 6] References Cited UNITED STATES PATENTS 1,471,971 10/1923 Miller 212/55 3,465,899 9/1969 Reuter et a]. 212/55 3,516,544 6/1970 Nakamura 212/55 Primary Examiner-Harvey C. Hornsby Assistant ExaminerMerle F. Maffei Atl0mey-Sughrue, Rothwell, Mion, Zinn & Macpeak ABSTRACT: A self-propelled crane is provided with a mast pivoted on a rotatable platform for movement between a horizontal and a vertical position. A telescopic jib is pivoted on the mast and the same cable and winch used to raise and lower a load from the tip of the jib is used to extend the jib when the telescopic jib sections are unlatched from each other. The same cable and winch may be used to raise the mast to the vertical position by securing the end of the cable to a stationary point below the pivot point of the mast. The mast may also be telescopic and a second cable and winch may be used to control both the angle of the jib relative to the mast and the extension of the telescopic mast when the parts thereof are unlatched from each other.

PATENIEDJM 41912 sum near 12 PMENTEB MI 4 B72 SHEET 03UF 12 PATENIEnJm 4:972 3531.988

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SHEET 110E 12 PATENTEB JAN 4 m2 SHEET l2 BF 1 2 SELF-PROPELLED CRANE The present invention relates to a selfpropelled crane, the mast and jib of which may be lowered to the horizontal on a revolving platform which is carried by a mobile chassis.

The present invention relates to a selfpropelled crane of this type, and more particularly it concerns the system for raising the mast and for unfolding the jib which is used to erect a crane of large size and which, moreover, is adapted to conform to the law regarding dimensions for vehicles when it is folded on its chassis.

In addition, unlike the majority of selfpropelled cranes known up to now, which include a jib linked directly to the platfonn, the crane provided by the invention has a jib carried on top of a mast which may or may not be telescopic. This allows the height below the crane hook to be increased, and all the space available between the pivot at the foot of the jib and the ground to be free of encumbrances.

According to the invention a selfpropelled crane comprises a chassis carried on wheels, and supporting a revolving platform, a mast carried by the platform and a jib carried by the mast, the mast being capable of swinging from a lowered position to a vertical position and the jib being capable of swinging on the mast from a lowered, substantially horizontal position to a raised position, the jib being telescopic, and cable means operated by a winch for extending the jib when it is raised.

Preferably the jib pivoted on the mast is telescopic, its head component including a sheaved hook on a lifting cable which is anchored at one end to the rear of the jibhead component, then passes over a pulley carried by the front of the jib foot component, then passes under a pulley fitted to the rear of the jib head component, then around a pulley block at the jibhead to support the lifting hook before returning to a pulley revolving on the shaft linking the jib to the top of the mast, the lifting cable passing finally over guide pulleys to reach the drum of a lifting winch carried on the revolving platform, a removable prop also being provided at the front of the jib foot component to bear the ground during the telescoping operation, and remotely controlled detachable means of latching being provided on the two sliding components of the telescopic jib.

Owing to this arrangement, the cranelifting cable itself may be used to telescope the jib and to unfold the mechanism to the working position.

On a first possible manufacturing variant, this lifting cable is used in addition for raising the mast by hooking the lifting hook to the revolving platform or to the carrying chassis, and for swinging the assembly of the mast and the folded jib.

Following another possible manufacturing variant, a drum, which may be disconnected, is provided on a second winch on the platform. This second winch is always provided to carry out the raising of the jib once the mast is erected.

Following another possible manufacturing variant, a telescopic mast is used, in which case the cable of the lifting winch is led in addition around a tackle between the base of the upper component of the mast and the top of the lower component. According to whether the two components of the mast are latched together or not, it will be seen that it is possible either to raise the jib or to telescope the mast.

Another variant is designed specially for a crane fitted with a mastbalancing system. It is known that such systems may call for considerable power on starting to raise the mast. In the particular case of the invention, in order to avoid this disadvantage it is intended to carry out the simultaneous raising of the mast and the jib with the minimum of effort at the start.

According to this variant, the invention is characterized in that the rear train of pulleys of the jibraising tackle is linked by a sling of constant length to one arm of a swingbar pivoted at its center on the platform, the other arm of this swingbar being linked by a cable to the top of the mast post, the said swingbar being fitted with a stop which limits its swing when thejibraising sling is drawn upon, while the cable attached to the top of the mast remains slack. Further to reduce the force needed at the start of raising, a third winch is provided on the platform to operate a special sheaved cable between the said platform and the foot of the mast. This third winch is used only to raise the mast.

It will be understood that at the start of raising, while the cable linking the top of the mast to the swingbar remains slack, this latter remains against its stop, so that the mastbalancing system does not become involved. It is only at the end of lifting, when the cable at the front tightens, that the bar swings and leaves its stop in order to play its part in balancing between this cable and the sling of the jibraising tackle.

The invention will be more clearly understood from the following description of several cranes constructed in accordance with the invention which are described by way of examples only. In the drawings:

FIG. I is a view in elevation of one form of propelled crane, folded in its transport position,

FIG. 2 shows the crane shown in FIG. I, on the work site, after the stabilizers are unfolded from the chassis and the platform has been rotated through a certain angle,

FIG. 3 is a side view corresponding to FIG. 2,

FIG. 4 illustrates the phase of raising the mast by means of the lifting cable of the jib,

FIG. 5 shows the first phase of raising the jib,

FIG. 6 shows the telescopic jib extended,

FIG. 7 represents schematically the remotely controlled latching system which is used on the two components of jib foot and jibhead, the assembly being shown in the retracted position,

FIG. 8 shows the device of FIG. 7 in the latched position,

FIG. 9 shows the crane in the working position, and shows its advantage over traditional cranes, having the jibs pivoted directly on the platform,

FIG. 10 shows, in the folded position, an alternative crane which has a winch with a special detachable drum for raising the mast, FIG. 11 is a partial plan view of the platform of the crane shown in FIG. 10,

FIG. 12 shows the mast raised in the case of the crane of FIG. 10,

FIG. 13 shows another crane in which the mast is telescopic,

FIG. 14 illustrates the beginning of the phase of raising the mast of the crane shown in FIG. 13,

FIG. 15 shows the mast after it is raised, which has automatically caused it to be extended to a certain height, L

FIG. 16 illustrates the phase of the final extension of the; mast,

FIG. 17 is a tackle plan, showing the run of the lifting cable in all the forms of crane according to the invention,

FIG. 18 is a tackle plan of the raising cable of a crane when the mast is telescopic,

FIG. 19 is a tackle plan of the jibraising cable when the mast is not telescopic,

FIG. 20, is a schematic vertical section of a telescopic mast, showing the system for latching its two components,

FIG. 21 is a transverse section corresponding to FIG. 20 the locking system being latched,

FIG. 22 is a lateral view corresponding to FIG. 20 when the locking system is unlatched,

FIG. 23 shows the crane assembly folded and contracted in the transport position,

FIGS. 24-26 show the successive phases of unfolding and raising the crane,

FIG. 27 shows in the unlatched position, the system of locking the two telescopic components of the jib,

FIG. 28 is a similar view of the latched position,

FIG. 29 is a schematic lateral view in the direction of the arrow VIII in FIG. 28,

FIG. 30 is a lateral view in the direction of the arrow IX in FIG. 28 showing the cam locking system provided to take up P y FIG. 31 shows the position of the balancing swingbar during the first phases corresponding to FIGS. 23, 24 and 25, and

FIG. 32 shows the position of this swingbar at the end of raising the mast, when the crane is in the working position (FIG. 26).

The selfpropelled crane shown in the drawings comprises a chassis 1 carried on wheels 2. The chassis is surmounted by a pivot 3 on which revolves a platform 4.

This platfonn is fitted with the following components:

a winch 5 for lifting the hook 6, which will be discussed I later;

a winch 7 for raising the jib; a directional mechanism, not shown, for controlling the rotation of the platform 4 on the pivot 3.

The front of the platform 4 is fitted with a pedestal 8 the top of which carries a horizontal shaft 9. The mast 10 of the crane may be lowered about the shaft 9. The top of the mast 10 carries a post 1 1 which, if required, may itself by capable of folding as shown in FIG. 1 by the dotted portion 11a, if this is made necessary by legal requirements regarding vehicle size. The post 11 is fixed to the top of the mast 10. In addition, another post 12 is pivoted on the mast l0, and a cable 13 of constant length connects it to the tip of the post 11.

On a lateral shaft 14 of the mast 10 is pivoted the foot component 15 of a telescopic jib. Inside this component 15 (FIGS. 6 to 8) slides a jibhead component 16. At its free end, the jib 15-16 carries a pulley block 17 from which is suspended the pulley block 18 of the lifting hook 6. The operation of this hook is controlled by the winch 5, by means of a lifting cable 19 the run of which has been shown in detail in FIG. l7. One of the ends of the cable 19 is anchored at a point 20 on the rear of the jibhead 16. Then the cable 19 passes over a pulley 64 carried by the front of the jib foot 15, then around a pulley 21 which is fitted to the rear of the jibhead l6, and over a pulley 22 which carries it to the pulley blocks 17 and 18 of the hook 6. The cable 19 then returns inside the jib 15-16 to a pulley 23 which is carried on the pivot shaft 14 of the jib on the mast 10. The pulleys 24 and 25 carried by the mast l guide the cable 19 to lead it to the drum of the winch 5, on to which it is anchored at its other end.

In all the variants illustrated in the drawings, the locking of the jibhead 16 to the foot 15 may be remotely controlled by a mechanism of the kind illustrated in FIGS. 7 and 8. For this a rod 26 is operated from the free end of the jibhead 16, the movement in one direction or the other causing two pairs of transverse sliding bolts 27 to be brought towards each other (FIG. 7) or to be moved apart (FIG. 8). For this purpose some oblique connecting rods 28 link each bolt 27 to the rod 26, providing two sets of toggle links. When the rod 26 is pushed by hand in the direction shown by the arrow 29, the bolts 27 move apart (FIG. 8) and lock the foot 15 to the head 16. On the contrary, if the rod 26 is pulled in the direction of the arrow 30 (FIG. 7) the bolts 27 retract so that the jibhead 16 may then slide freely in the jib post 15.

Finally a detachable prop 31 (FIGS. and 6) may be fixed to the forward end of the jib foot 15, so as to hold it in the position shown in FIG. 5 by resting on the ground.

There is shown in FIGS. 1 to 9 and 19 to 22 a crane with a mast which is not telescopic. In this case the raising of the jib -16 is carried out from a winch 7, by a cable 32 the run of which appears in detail in FIG. 19. This cable leaves the winch 7 to pass over a pulley 33 placed at the top of the post 11, then over a pulley 34 fitted to the free end of the pivoted post 12, before acting upon the end of the jibhead 16 through a tackle 35.

The operation of the crane so far described is as follows:

The folded mechanism shown in FIG. 1, constitutes a selfpropelling assembly which satisfies the legal requirements for road vehicles. It is balanced on its chassis 1 and can move along the road at a relatively high speed.

0n arriving at the work site, the mechanism is chocked in a horizontal position by unfolding stabilizers 37 (FIGS. 2 and 3) under the chassis 1, then the platform 4 is turned through 90 so that the mast 10 and the jib 15-16 lie transversally across the chassis 1. The hook 16 is then hooked to the chassis I, as shown in FIG. 3, then the lifting winch 5 is operated so as to wind in the cable 19 whilst the raising winch 7 is allowed to run free. In this way the fixed hook 6 and the pulleys 17 of the jibhead are drawn together, so that the assembly of the mast l0 and of the jib 15-16 is raised vertically turning around the shaft 9, as shown in FIG. 4. In this position the mast I0 is pegged to the platform 4 at a point 38. Hence the mast 10 is from now on fastened to the revolving platform.

The hook 6 is unhooked from the chassis 1 while the jib foot component 15 and the jibhead 16 are released by unlatching the latching mechanism shown in FIGS. 7 and 8.

By winding the cable 32 on to the winch 7 the raising of the jib is begun in the direction shown in FIG. 5 by the arrow 39. The detachable prop 31 is put in place and rests vertically on the ground. The jibhead 16 is brought out from the jib foot 15 by the operation of the winch 5. In fact, thanks to the tackle illustrated in FIG. 17, it will be seen that any pull exerted on the cable 19 makes the jibhead 16 move out in the direction of the arrow 40 (FIG. 6). When the head 16 is completely out, it is latched to the foot of the jib 15 by means of the bolts 27 of the rod 26 (FIGS. 7 and 8). Then the prop 31 is removed, then the extended jib 15-16 is raised as a unit with the aid of the raising winch 7 and its cable 32. Once the desired working angle is reached, it will be seen that the space available below the jib, which has been shown schematically in FIG. 9 by the shape of the line 41, is appreciably greater than the useful space 42 with a jib 43 which might be attached in the conventional manner, not to a mast 10, but directly on a shaft 44 of the platform 4.

There is shown in FIGS. 10, 11 and 12 an alternative crane in which the raising of the nontelescopic mast 10 is carried by a third winch drum 44 which may be disconnected. This drum operates a special cable 45, which forms a tackle between a pulley block 46 can'ied by the foot of the mast 10 and a pulley block 47 fitted to the platform 4.

In this case, the raising of the mast 10 is carried out by means of the engaged drum 44, whilst the top of the jib runs on a guide roller 48 fitted to the front of the removable propulsion unit 36 (FIG. 12). The rest of the operation is carried out in the manner already described.

There is shown in FIGS. 13 to 16 and 18 an alternative construction in which the telescopic jib 15-16 is carried by a mast 49-50 which is also telescopic.

The lower component 49 of the mast is mounted on the pivot 9 as in the previous cases. Here the difference lies essentially in the run of the raising cable 32 operated by the winch 7 For this purpose (FIG. 18) the cable 32 leaves the winch 7 to pass over a pulley 51 at the top of the lower component 49. Then the cable 32 passes round the pulleys 52 and 53 placed at the base of the upper component 50, then it goes up again over a pulley 54 fitted at the top of the component 49, down again around a pulley 55 fitted inside the foot of the component 50, and finally it returns upwardly inside the mast to a pulley 56 which guides it on to the pulley 33 at the end of the post 11. Then the cable 32 runs as already described, namely it passes over the pulley 34 and is anchored at the end 57 of the jibhead, with or without the interposition of tackling between the pulley 34 and the end 57.

The operation of this form of crane with a telescopic mast is as follows:

At first the fixed hook is hooked on to the platform 4, as has been already indicated (FIG. 14); then the lifting cable 19 is wound on to the winch 5. This brings the pulley block at the jibhead l7 nearer to the fixed point constituted by the hook 6. There results from this a simultaneous composite movement:

a raising of the mast 49-50 and the jib 15-16 up to the vertical, in the direction indicated on FIG. 15 by the arrow 58, and

a partial extension of the upper component 50 of the mast (arrow 59), and of the jib assembly 15-16, the end 57 of which comes into close proximity with the fixed hook 6.

Owing to this composite movement the jibhead follows a curved trajectory 60 which allows it to avoid the propulsion unit 36.

The mast which is thus brought vertical is therefore already partially extended in the position shown in FIG. 16 in broken lines. During all the preceding operation the drum of the extension winch 7 is of course stationary.

The mast is pegged in the vertical position and then the raising of its upper component is completed by winding the cable 32 on to the winch 7 whilst leaving free the lifting winch 5. When the mast is completely extended the two components 50 and 49 are latched to each other by means of a mechanism controlled from the foot. An example of this mechanism is shown in FIGS. 20, 21 and 22. For this purpose there are provided on the side of the upper component 50 some wedge shaped shoes 61 which can bear on some horizontal sliding bolts 62. The latter are guided by flanges 63 arranged inside the component 49. These bolts 62 are withdrawn by pulling a rod 64 from the mast foot. This rod is situated between the components 49 and 50, as are the flanges 63, the bolts 62 and the shoes 61..

It will be seen that when the upper component 50 is latched to the lower component 49 (FIGS. and 21) its own weight acting on the oblique shoes 61 takes up transverse play and holds the two components 49 and 50 finnly together.

To lower the telescopic mast 49-50, it is sufi'rcient to start a raising movement for the upper element 50 which has the effect of unwedging the latch pins 62. Then these latter are withdrawn and the component 50 is lowered.

In the difierent examples which have been described, the refolding of the crane is carried out by receiving the process,

until there is again obtained a selfpropelling assembly of the kind illustrated in FIGS. 1, 10 or 13.

In the constructions shown in FIGS. 23 to 32, another post 12 is pivoted on the mast 10. This post carries at its top a pulley 34 around which passes a jib cable 101. As in the previous examples, this cable 101 passes over a pulley 33 at the top of the post 11 before ending at the drum of a raising winch 7 mounted on the platform 4. After the pulley 34 this cable 101 forms a tackle between two pulley blocks 102 and 103. The shaft of the pulleys 102 is connected to the end 104 of the jibhead 16 by a sling 105. In addition, the shaft of the pulleys 103 is joined by a sling 106 to one end 107 of a balancing swingbar 108 (FIGS. 24, 26, 31 and 32). This sling 106 passes successively around a pulley 109, coaxial with the pulley 34 on the end of the pivoted post 12, and over a pulley 110 coaxial with the pulley 33 at the top of the fixed post 11. It will be seen therefore that by operating the winch 7 of the raising cable 101 the sling 106 will in practice be held permanently taut.

As in the case of the arrangements shown in FIGS. 1 to 22, a cable of constant length 13 links the top of the pivoted post 12 to the top of the fixed post 11.

The balmcing swingbar 108 is pivoted at its center to a fixed shaft 111 carried by a flange 112 on the platform 4. The end of the other arm of the swingbar 108 is fitted with a shaft 113 to which a sling 114 is hooked. The latter links the swingbar 108 to an anchorage point 115 fitted to the top of the fixed post 11 (FIGS. 24, 25 and 26).

Finally, a last characteristic of this arrangement consists in providing on the platform 4 a third winch drum 116, which operates only a cable 117. The latter forms a tackle between two pulley blocks 118 and 119 fixed respectively to the platform 4 and the foot of the mast 10 beyond the pivot shaft 9 (FlG. 24). This cable 117 and the winch 116 are provided solely to carry out the raising of the mast.

The swingbar 108 is fitted in such a way that its end 120 corresponding to the shaft 113 comes to rest on the platform 4 (FIGS. 23, 24, 25 and 31) so long as the sling 114 remains slack while the sling 106 is taut.

The sizes chosen for the various components of the crane are selected so as to form precisely a plan which allows the simultaneous raising of the mast 10 and the jib 15-16 during the operations which will now be described.

The operation is as follows:

At the start the crane folded in the transport position is seen as shown in FIG. 23. The contracted jib is lowered to the horizontal as is the mast 10. The sling 106 is held appreciably taut by the cable 101 and by its tackle between the pulleys 102 and 103, so that the swingbar 108 is against the platform 4, the cable of the sling 114 remaining slack. From this position, the jib 15-16 is first extended in the horizontal position (FIG. 24). For this it suffices to wind the lifting cable 19 on to the winch 5, while the winch 7 is freed to allow the cable 101 to run slack. The jibhead 16 moves outwards as shown by the arrow 121.

At the end of its travel, the two components 15 and 16 are latched together by means of a system shown in FIGS. 27 to 30. This system comprises two pairs of opposed sliding bolts 122 and 123 fitted to the jibhead 16. The rear of each bolt 122 is linked to the rear of the opposite bolt 123 by means of a pivoted arm 124. These two arms 124 cross at a pivot 125. Connecting rods 126, each pivoted to one of the arms 124, are linked by a common pivot 127 to a longitudinal bar 128 which is able to slide inside the jibhead 16 in two guides 129 on this" head 16. The bar 128 carries a transverse pulley 130 which is engaged in a slotted opening in an operating arm 131. This arm is pivoted by a shaft 132 on one of the sides of the jibhead 16 and it ends at the level of the opposite side at a handle 133. It will be seen that it is sufficient for the operative to displace the handle 133 in the direction of the arrow 134 (FIG. 27) to insert the bolts 122 and 123, that is to say to move them from the retracted position (FIG. 27) to the inserted position (FIG. 28). Thus each bolt 122 or 123 of the jibhead 16 is engaged in a notch 135 provided on the mast foot 15 in the position corresponding to the total extension of the jib 15-16.

In addition, to compensate for play or wear, there are provided on the lateral faces of the mast foot 15, two opposed shafts 136 on each of which a plate 137 turns. This plate has cut in it a kidneyshaped slot 138. The external edge 139 if this slot follows a trajectory similar to that of a spiral, that is to say that at one of its ends 139a it is further from the shaft 136 than at the other end 13%. The assembly is arranged so that the corresponding bolt 123 engages freely in the slot 138 when the plate 137 is disposed with the end 139a of this slot opposite the bolt 123. After the jibhead 16 is positioned on the foot and the bolts 123 are inserted (FIG. 28, arrows 140) it suffices to strike the end of the plate 137 as shown in FIG. 30 by the arrow 141 to cause this plate to rotate until it is stopped by the pressure of the edge 139 against the bolt 123 which is pressed against the bottom of the corresponding notch 135. At the end of the operation, the direction of each plate 137 varies in relation to the degree of play and wear which have thus been taken up.

Once the jib is extended and latched (FIG. 24), the raising of the mast is proceeded with by operating the winch 116 to wind in the cable 117. At the same time the raising winch 7 of the cable 101 is kept fixed. Since the crane assembly has been given dimensions in such as way that this operation is accompanied by a shortening of the curvilinear (FIG. 24) or rectilinear (FIG. 25) distance A which separates the end of the jibhead and the top of the fixed post 11, it will be understood that the raising of the mast by swinging it around the shaft 9 in the direction of the arrow 142 (FIG. 25) is accompanied by a raising of the jib 15-16 which pivots around the shaft 14 (FIG. 25 arrow 144). Simultaneously the distance B separating the ends 113 and 115 of the sling 114 is increased. This sling 114 therefore comes under tension as the mast is raised, and it is completely taut when the mast l0 approaches the vertical (FIG. 25). Until this moment the swingbar 108 had remained against the platform 4. It will be seen therefore that the balancing system 106-114 of the mast 10 does not exert any influence at the start of the raising of this mast 10.

Beyond the position illustrated in FIG. 25, the slings 106 and 114 being both taut, the swingbar 108 ceases to rest against the platform 4 and it swings around its pivot 111 so as finally to occupy the position shown in FIGS. 26 and 32. Thus it may play its balancing role when the crane is in the working position.

At the end of these operations, the mast 10 is locked by means of a peg 143 which is put into place on its foot.

The refolding of the crane is carried out by a process the reverse of that which has just been described.

More specifically the jib may be retracted by unlocking the latching bolts between two jib components. With the jib in the position shown in FIG. 9 gravity would accomplish the retraction upon supplying slack to cable 19. Also, cable 32 could be reeled in to retract the jib. If a telescopic mast is utilized it is sufficient to merely unlatch the mast sections and allow gravity to retract the mast under the control of cable 32. Upon unlatching the base of the mast at 38, the mast will lower to the horizontal position under the control of the particular cable arrangement used to hoist the mast in the first place.

lclaim:

l. A selfpropelled crane comprising a wheeled chassis, a rotatable platform mounted on said chassis, mast means pivotally mounted on said platform for movement between a substantially horizontal position and a substantially vertical position, telescopic jib means pivotally mounted on said mast means for movement between a position parallel to said mast means when said mast means is in the substantially horizontal position and a plurality of positions extending outwardly from said mast means when the mast means is in the substantially vertical position, latching means operable independently of the inclination of said jib means relative to said mast for latching said jib means in the retracted telescoped position and in the extended position, guide pulley means mounted on said telescopic jib means, first winch means mounted on said platform, load supporting means, first cable means traversing said guide pulley means and operatively connected to said winch means and said load supporting means whereby said first cable means controls the raising and lowering movement of said hoisting means when said latching means prevents telescopic movement of said jib means and controls the telescopic movement of said jib means when said latching means is unlatched to allow telescopic movement of said jib means, said jib means comprising a foot component and a head com- 'ponent telescopically received therein, said first cable means being anchored at one end to the lower end of said head component and extending over a guide pulley carried by the upper end of said foot component, under a guide pulley fitted to the lower end of said head component, around a guide pulley at the top of the head component and over guide pulleys to said first winch means whereby when said first cable means is wound on to the winch said first cable means draws the guide pulley at the lower end of the head" component toward the guide pulley at the upper end of the foot component thereby extending the head component outwardly from the foot component.

2. A selfpropelled crane as set forth in claim 1 wherein the guide pulley at the top of the head component is part of a sheave for the hoisting means.

3. A selfpropelled crane comprising a wheeled chassis, a rotatable platform mounted on said chassis, mast means pivotally mounted on said platform for movement between a substantially horizontal position and a substantially vertical position, telescopic jib means pivotally mounted on said mast means for movement between a position parallel to said mast means when said mast means is in the substantially horizontal position and a plurality of positions extending outwardly from said mast means when the mast means is in the substantially vertical position, latching means operable independently of the inclination of said jib means relative to said mast for latching the jib means in the retracted telescoped position and in the extended position, guide pulley means mounted on said telescopic jib means, first winch means mounted on said platform, load supporting means, first cable means traversing said guide pulley means and operatively connected to said winch means and said load supporting means whereby said first cable means controls the raising and lowering movement of said hoisting means when said latching means prevents telescopic movement of said jib means and controls the telescopic movement of said jib means when said latching means is unlatched to allow telescopic movement of said jib means, second winch means second cable means operably connected to said second winch means and said rb means 0 control the position of said jib means relative to said mast means, block and tackle means interposed along said second cable means parallel to said telescopic jib means and swingbar means pivotally mounted intermediate the ends thereof on said platform, sling means of constant length connected between the ends of the block and tackle adjacent the mast means a one arm of said swingbar means, additional swing means connecting the other arm of said bar to the top of said mast means whereby said jib means will be raised relative to said mast means upon raising of said mast means to the vertical position.

4. A selfpropelled crane as set forth in claim 3, wherein third winch means are provided on said platform and special sheathed cable means are operatively connected between the foot of said mast means and said third winch means to raise said mast means.

5. A selfpropelled crane comprising a wheeled chassis, a rotatable platform mounted on said chassis, mast means pivotally mounted on said platform for movement between a substantially horizontal position and a substantially vertical position, telescopic jib means pivotally mounted on said mast means for movement between a position parallel to said mast means when said mast means is in the substantially horizontal position and a plurality of positions extending outwardly from said mast means when the mast means is in the substantially vertical position, latching means operable independently of the inclination of said jib means relative to said mast for latching said jib means in the retracted telescoped position and in the extended position, guide pulley means mounted on said telescopic jib means, first winch means mounted on said platform, loadsupporting means, first cable means traversing said guide pulley means and operably connected to said winch means and said load supporting means whereby said first cable means controls the raising and lowering movement of said hoisting means when said latching means prevents telescopic movement of said jib means and controls the telescopic movement of said jib means when said latching means is unlatched to allow telescopic movement of said jib means, said latching means including two pairs of bolts which slide in opposite directions, control means operable by a single handle to move said bolts, said bolts being carried on said jib head component, sockets located in said jib foot component for receiving said bolts, adjustment means for engaging at least one of said bolts in the last position comprising a plate having a kidneyshaped slot with one edge which forms a spiral cam, said plate being pivoted on said jib foot component with said one of said bolts engaged in said slot.

6. A selfpropelled crane according to claim 4 wherein the dimensions fonning the sum total of the various paths which the elements follow when the structure is operated are so chosen as to obtain a reduction of the straight line distance between the tip of the jib means and top of the mast means in proportion as the mast is raised.

7. A selfpropelled crane according to claim 6 wherein said the sum total of the various paths which the elements follow when the structure is operated is formed in addition so that the distance separating the two ends of the sling anchored to the top of said mast means and to one of the arms of the balancing swingbar means increases in proportion as the mast means is raised.

8. A selfpropelled crane according to claim 7 wherein said swingbar means moves from its stop position only when the mast means which is being raised approaches the vertical. 

1. A self-propelled crane comprising a wheeled chassis, a rotatable platform mounted on said chassis, mast means pivotally mounted on said platform for movement between a substantially horizontal position and a substantially vertical position, telescopic jib means pivotally mounted on said mast means for movement between a position parallel to said mast means when said mast means is in the substantially horizontal positIon and a plurality of positions extending outwardly from said mast means when the mast means is in the substantially vertical position, latching means operable independently of the inclination of said jib means relative to said mast for latching said jib means in the retracted telescoped position and in the extended position, guide pulley means mounted on said telescopic jib means, first winch means mounted on said platform, load supporting means, first cable means traversing said guide pulley means and operatively connected to said winch means and said load supporting means whereby said first cable means controls the raising and lowering movement of said hoisting means when said latching means prevents telescopic movement of said jib means and controls the telescopic movement of said jib means when said latching means is unlatched to allow telescopic movement of said jib means, said jib means comprising a foot component and a head component telescopically received therein, said first cable means being anchored at one end to the lower end of said head component and extending over a guide pulley carried by the upper end of said foot component, under a guide pulley fitted to the lower end of said head component, around a guide pulley at the top of the head component and over guide pulleys to said first winch means whereby when said first cable means is wound on to the winch said first cable means draws the guide pulley at the lower end of the head component toward the guide pulley at the upper end of the foot component thereby extending the head component outwardly from the foot component.
 2. A self-propelled crane as set forth in claim 1 wherein the guide pulley at the top of the head component is part of a sheave for the hoisting means.
 3. A self-propelled crane comprising a wheeled chassis, a rotatable platform mounted on said chassis, mast means pivotally mounted on said platform for movement between a substantially horizontal position and a substantially vertical position, telescopic jib means pivotally mounted on said mast means for movement between a position parallel to said mast means when said mast means is in the substantially horizontal position and a plurality of positions extending outwardly from said mast means when the mast means is in the substantially vertical position, latching means operable independently of the inclination of said jib means relative to said mast for latching the jib means in the retracted telescoped position and in the extended position, guide pulley means mounted on said telescopic jib means, first winch means mounted on said platform, load supporting means, first cable means traversing said guide pulley means and operatively connected to said winch means and said load supporting means whereby said first cable means controls the raising and lowering movement of said hoisting means when said latching means prevents telescopic movement of said jib means and controls the telescopic movement of said jib means when said latching means is unlatched to allow telescopic movement of said jib means, second winch means, second cable means operably connected to said second winch means and said jib means to control the position of said jib means relative to said mast means, block and tackle means interposed along said second cable means parallel to said telescopic jib means and swingbar means pivotally mounted intermediate the ends thereof on said platform, sling means of constant length connected between the ends of the block and tackle adjacent the mast means a one arm of said swingbar means, additional swing means connecting the other arm of said bar to the top of said mast means whereby said jib means will be raised relative to said mast means upon raising of said mast means to the vertical position.
 4. A self-propelled crane as set forth in claim 3, wherein third winch means are provided on said platform and special sheathed cable means are operatively connected between the foot of said mast means and said third winch means to raise said mast Means.
 5. A self-propelled crane comprising a wheeled chassis, a rotatable platform mounted on said chassis, mast means pivotally mounted on said platform for movement between a substantially horizontal position and a substantially vertical position, telescopic jib means pivotally mounted on said mast means for movement between a position parallel to said mast means when said mast means is in the substantially horizontal position and a plurality of positions extending outwardly from said mast means when the mast means is in the substantially vertical position, latching means operable independently of the inclination of said jib means relative to said mast for latching said jib means in the retracted telescoped position and in the extended position, guide pulley means mounted on said telescopic jib means, first winch means mounted on said platform, load-supporting means, first cable means traversing said guide pulley means and operably connected to said winch means and said load supporting means whereby said first cable means controls the raising and lowering movement of said hoisting means when said latching means prevents telescopic movement of said jib means and controls the telescopic movement of said jib means when said latching means is unlatched to allow telescopic movement of said jib means, said latching means including two pairs of bolts which slide in opposite directions, control means operable by a single handle to move said bolts, said bolts being carried on said jib head component, sockets located in said jib foot component for receiving said bolts, adjustment means for engaging at least one of said bolts in the last position comprising a plate having a kidney-shaped slot with one edge which forms a spiral cam, said plate being pivoted on said jib foot component with said one of said bolts engaged in said slot.
 6. A self-propelled crane according to claim 4 wherein the dimensions forming the sum total of the various paths which the elements follow when the structure is operated are so chosen as to obtain a reduction of the straight line distance between the tip of the jib means and top of the mast means in proportion as the mast is raised.
 7. A self-propelled crane according to claim 6 wherein said the sum total of the various paths which the elements follow when the structure is operated is formed in addition so that the distance separating the two ends of the sling anchored to the top of said mast means and to one of the arms of the balancing swingbar means increases in proportion as the mast means is raised.
 8. A self-propelled crane according to claim 7 wherein said swingbar means moves from its stop position only when the mast means which is being raised approaches the vertical. 